St. Tammany farmer. [volume] (Covington, La.) 1874-current, 1887-05-07
w. q. kENTZEL, Editor.

amounting to certainty" Indeed
merely attempting to blow out tn,
flame within the lamp may cause it {,
ignite an inflammable mixture. Happil,
invention has not been long benin.
necessity. and there are at least half-a
dozen forms of lamp which are saf,
under current velocities exceeding thre,
thousand feet per minute. Everybod,
will agree with the conclusion of tn,
Royal Commissioners that whilst il
would be unwise to make a particular
lamp compulsory on the ground tina,
diihculties might thereby be thrown ir
the way of introducing improvement.
IN future. it is nevertheless desirable
that some control should be exercised in
reference to the kind of lamps to be EN-.
ployed in coal-mines, and that only those
lamps should be used which are author.
lied from time to time by the Secretary
Of State.
Fire-damp. however, is not the most
formidable sf the causes of colliery
explosions. 1t is doubtful. indeed,
whether single one of the more dis
astrous explosions of modern times can
be directly and wholly attributed to its
action. 1t is significant that violent
explosions seldom occur nowadays in
very wet pits, although the air in them
frequently contains fire-damp. More
over, when explosions do occur in such
pits they rarely extend over a large
area, and the loss of life from them is
comparatively small. Such catastro-
phes as those of Abercarne, Risca,
Seaham and Penygraig. where
hundreds of men and boys are
killed. and where evidence of the ex-
plosion is to be met with in nearly all
parts of the pits. almost invariably
happen in dry and dusty pits 1t hardly
admits of question that explosions Of
this kind are dependent upon the pres
ence of this dust Dust explosions in
flour-mills have long been known, but
it is only within the last few years that
the action Of finely divided coal-dust in
initiating or propagating colliery ex-
plosion has received much attention.
The atmosphere of deep dry mine is
always impregnated with more or less
dust 1t settles everywhere. not only in
the working places, but in the intake
and haulage roads. 1t is not only on
the floor, but hangs from the roof
and timbers. and is heaped up on the
ledges. A violent movement Of the air
dislodges it in clouds; if naked flame
be introduced into such q cloud it in
flames with explosive violence and the
conclusion of air is followed BY fresh
clouds OF dust through which the flame
is propagated.
With sudden blaze diffusd infiames the air"
Milton said this Of Sunpowder; it is
even truer of coal-tlust.
Now there are many conditions in the
ordinary working Of coal mine which
may occasion these violent movements
Of the air. and chief among them is
the prevalence Of what is techni-
caily known as ''shot-firing''-that is,
blasting by means Of gunpow,ler. Gum
powder is uscsl in the mine either for
bringing down the coal or for removing
stone. in order. for example. to make
roads for the passage Of horses, and for
engine planes, etc. A hole is driven or
drilled into the coal or stone. into
which certain quantity Of powder. to-
gether with a fuse, is introduced, and
the rest Of the hole is '.stemmed'' or
'ramped'-that is, filled up with small
stones and earth or, too frequently,
with small coal itself. The fuse is iy-
nited and the workmen retire either in |
to a ''refuge hole'' or round a corner
until the blast is made, Occasionally |
it happens when the charge of gum
powder is too large. or when it is inn
perfectly stcmmed. or when the rock is
hard. that the powder blows
out the stemming and there is violent
of air. and from the mouth
Of the ,lrill-hole there issues a flame
the length of which will be greatly
increased if small coal has been
used in the stemming. Indeed. it is
not necessary for the shot to be '.blown
OUT to produce either the fame or a
of air sufficient to dislodge
the infammable dust We have here q
condition of things which may be high
y dangerous in dusty pits. 1t has been
proved over and over again that shot
firing has been the immediate precursor
II some Of the most disastrous colliery
explosions on record. The influence Of
lust in at least propagating an explosion
8 now generally recognized by mining
engineers and colliery managers, but
t is still a moot point with some
it is capable of initiating an
explosion or, indeed, Of propsgating it
n the absence Of fire-lamp. There is,
lowevcr. considerable body of evil
ence to show that whilst the explosive
haracter Of a dusty atmosphere may
e greatly augmented by the presence
( fire-damp. dust alone may be suffi-
lent to bring about the most disastrous
xplosions. It's known that explosions
ave occurred simultaneously with the I
ring Of shots in stone. and certain Of +,
1ese shots have been fired in dusty
lain intake-road. and at points where
arrents Of air of over $4,000 cubic feet
er minute were passing. It is almost
except on the theory of
he sudden outburst Of gas at places 4
here it is in the highest degree improb- !
II 1